Bough a vice looks like an Abwood?
It works but as you unscrew it the screw comes out and the jaw doesnt unless you help it along
So how do I get it apart and whats up with it?
Take of the 2 front bolts and unwind the screw out..then just slide it off. It has a clip washer that screws down the thread and sits in a groove, its this that pushes on to the jaw to push it out.
Your vice appears to be a 6" Abwood, like the one in the first photo. As @roofman said, there is a retaining clip to hold the screw in its holder. Here are a couple of photos of my smaller Abwood. The design is the same, but if you also want to remove the top slide completely, you need to loosen the gib screws on the side and remove the movable jaw face so that it slides clear of the threaded bronze bushing.